Kurdish officials say Turkish forces have been dropping napalm shells in what they describe as indiscriminate bombing of the countryside around Afrin, a Kurdish enclave that's taking the brunt of a Turkish offensive launched a week ago and called, inexplicably, Operation Olive Branch.

"The Turkish army uses the forbidden weapon napalm in Afrin against civilians," Syrian-Kurdish politician Îlham Ehmed tweeted overnight Saturday. The accusation was dismissed by the Turkish military, who say Kurdish propagandists hope to excite international opposition to Turkey.

International law does not prohibit the firing of napalm, a highly flammable sticky jelly used in incendiary bombs, against military targets, but it does ban it from being unleashed on civilians.

There has been no independent verification of napalm being used during the Turkish offensive — and establishing the accuracy of claims by either sides is challenging with both the Turks and Kurds waging a war of narratives.

On Saturday President Recep Tayyip Erdogan startled Western officials by threatening to expand the incursion along the whole of the border with Syria in his bid to crush the YPG, which he describes as a terrorist organization.' The Turkish leader's threat prompted French foreign minister Jean-Yves Le Drian to urge Turkey to act with restraint in Syria in a phone conversation with his Turkish counterpart Mevlut Cavusoglu.

Turkey's President Recep Tayyip Erdogan addresses his ruling party members in Ankara, Jan. 26, 2018. Erdogan has vowed to extend a Turkish cross-border offensive in northern Syria eastward.

Claim and counter-claim

Determining the accuracy of the casualty toll is also proving difficult amid claim and counter-claim. Syrian political activists on the ground in northern Syria say both sides are exaggerating losses inflicted on the other.

Military officials in Ankara Sunday claimed that Turkish forces and their Syrian rebel allies, remnants of the Free Syrian Army that led the fight against Syrian President Bashar al-Assad, have killed or captured more than 484 Kurdish militiamen since launching Operation Olive Branch.

And they say that in the week since the beginning of an incursion that threatens to unravel U.S. policy in Syria only three Turkish soldiers have been killed and 30 injured, while 13 Syrian rebels have been killed and 24 wounded.

The Turkish military is blocking journalists from entering Syria to cover first-hand the fighting, but they did organize a tour for reporters, who last week were taken to see a hospital and school in the Syrian border town of Azaz, both rebuilt by the Turks after their 2016 offensive in northern Syria. Prompted by their teachers, Syrian refugee children told reporters they were grateful to Turkey for the school.

The Kurds are offering a starkly different version of what is underway in northern Syria in the countryside around Afrin, posting videos of Turkish shelling and of civilians, including children, injured in Turkish bombardments. They have posted videos also of foreign volunteers, including several Americans, who joined the YPG to battle the Islamic State terror group, but who say they now will go to Afrin to defend it from the Turks.

Families take shelter in basements in the Kurdish town of Jandairis near the Syrian-Turkish border, west of the city of Afrin, Jan. 26, 2018.

"The Turks are terrorists," said one American volunteer in a video posted last week by the YPG press office. Another said: "We are ready to go to Afrin to fight the Turkish invasion force. We have been training for a significant amount of time in tactics that work against any force."

Slow progress

Analysts say Operation Olive Branch appears to be making only slow progress. That may be due partly to inclement weather — the region has seen days of rain and low temperatures, and muddy conditions are making it hard going for armored vehicles.

Turkish officials concede their forces are moving slowly but say they are doing so in order to safeguard civilians. "The only things being targeted are terrorists, and any shelters, pits, weapons, vehicles, and equipment that belong to them," the Turkish army said Saturday in a statement, adding the incursion is "successfully continuing as planned."

Turkey says the main objective of Operation Olive Branch is to "cleanse" its border with Syria of the YPG, which it describes as an affiliate of Turkey's own outlawed Kurdish separatist group, the Kurdistan Workers' Party (PKK), which has waged a three-decade-long insurgency against Ankara.

A damaged house is seen in the Syrian town of Rajo in the Afrin District, Jan. 26, 2018.

Turkey shares a 911-kilometer-long border with Syria, around two-thirds of which is currently under YPG control. Turkish officials say they fear that the YPG will use their hold on a swathe of northern Syria to launch attacks against Turkey, much as the PKK has done for years from territory it occupies in northwest Iraq.

While Turkey has a clear advantage in the skies — the YPG has no air force — the Kurdish militiais a formidable foe on the ground. Many of its top military leaders are PKK veterans, who have had years of experience battling Turkey — which has NATO's second-largest army. And its militiamen, seen by the U.S. as their best ground allies against the Islamic State terror group, are battle-hardened from months of confronting the jihadists and have benefited from arms supplies and training by the U.S. military.

According to the Syrian Observatory for Human Rights, a Britain-based network that gathers information from political activists on the ground in Syria, there have been fierce skirmishes the past 24 hours west of Afrin with continuous Turkish shelling of the villages of al-Anquz, Baflun and Qatma as well as the towns ofRaju and Jendires.

The Observatory says the death toll it has been able to verify includes 59 YPG fighters, 69 Syrian rebels and seven Turkish soldiers.

Calls for restraint

Several countries, including the U.S., Britain and France, have expressed alarm over the incursion, but no Western country has insisted Turkey halt the military operation.They have called for restraint and for the incursion to be limited.

On Saturday, Turkish officials said Ankara and Washington have agreed to "de-escalate tensions" between them over the YPG. "We may have difference of opinions on some issues but we are allied countries," H.R. McMaster, U.S. national security adviser, told President Erdogan's chief foreign policy advisor, during a phone conversation on January 27.

A January 24 call between President Donald Trump and his Turkish counterpart led to a dispute between U.S. and Turkish officials over what was agreed. Turkish officials say Washington and Ankara have now agreed to issue formal presidential statements following any future phone conversations between Trump and Erdogan.

According to Turkish officials, McMaster emphasized that no more weapons will be supplied to the YPG,a commitment the U.S. had already made in recent weeks. The Turks are also demanding that the U.S. should retrieve any stored weapons from Northern Syria earmarked for the YPG and that all military training or logistical support should cease.

Analysts say U.S. officials, who have been accused of sending conflicting signals about the Turkish incursion, are caught in the middle between Turkey, a fellow NATO member, and the U.S.'s Kurdish ground allies, who have been crucial in the fight against IS in Syria.